Abstract

KCl:Sn2+phosphors were synthesized from aqueous KCl/SnCl2 solutions. Solvents with a molar ratio of KCl : SnCl2 = 1 : M (M = 0 − 5) were dissolved in de-ionized water. The optical properties of the synthesized phosphors were investigated by photoluminescence(PL) analysis, PL excitation spectroscopy (PLE), and PL lifetime measurements. KCl:Sn2+phosphor synthesized with M = 0.1 exhibited the strongest PL emission in the green (AT band) and red spectral regions (R band). The phosphors synthesized with M ≥ 1 were composites of various potassium chlorostannates and emitted light in the red spectral region (R band). Annealing the M = 0.1 phosphor in dry N2 resulted in a PLspectrum that was the same as those usually observed in melt-grown KCl:Sn2+phosphors (i.e., exhibiting only the AT emission band). Annealing also led to a change in the PL decay characteristic from a double exponential curve to a single exponential curve. The AT and R emission bands had nearly the same PLEspectra and were related to the deexcitation of the Sn2+ (5s5p) ions in KCl.

Received 18 August 2011Accepted 27 October 2011Published online 05 December 2011

Acknowledgments:

The authors would like to thank T. Miyazaki, T. Nakamura, and H. Oike for their experimental support and useful discussions. This work was supported by a Grant-in-Aid for Scientific Research (B) (23360133) from the Ministry of Education, Culture, Sports, Science and Technology, Japan.